The Infra-Red Spectrum of Methyl Fluoride

Yates, K.; Nielsen, Harald H.

doi:10.1103/physrev.71.349

Cited by 19 publications

(6 citation statements)

References 9 publications

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“…However, this was analyzed for the original proposal of opto-electrical cooling [15] where it was found that even for CF 3 H with much smaller rotational constants, spontaneous decay with ∆J = 2 is marginal even for fields as large as 100 kV/cm. Second, it is well known that the v 1 C-H vibrational stretch mode of CH 3 F is coupled to the 2v 2 and 2v 5 modes via a strong Fermi-resonance [31,32]. As a result, spontaneous decay to the first excitation of the v 5 mode will occur, with a rate of about 1 − 2 Hz [33].…”

Section: Methodsmentioning

confidence: 99%

Sisyphus cooling of electrically trapped polyatomic molecules

Zeppenfeld

Englert

Glöckner

et al. 2012

Nature

192

188

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The rich internal structure and long-range dipole-dipole interactions establish polar molecules as unique instruments for quantumcontrolled applications and fundamental investigations. Their potential fully unfolds at ultracold temperatures, where a plethora of effects is predicted in many-body physics [1,2], quantum information science [3,4], ultracold chemistry [5,6], and physics beyond the standard model [7,8]. These objectives have inspired the development of a wide range of methods to produce cold molecular ensembles [9][10][11][12][13][14]. However, cooling polyatomic molecules to ultracold temperatures has until now seemed intractable. Here we report on the experimental realization of opto-electrical cooling [15], a paradigm-changing cooling and accumulation method for polar molecules. Its key attribute is the removal of a large fraction of a molecule's kinetic energy in each step of the cooling cycle via a Sisyphus effect, allowing cooling with only few dissipative decay processes. We demonstrate its potential by reducing the temperature of about 10 6 trapped CH 3 F molecules by a factor of 13.5, with the phase-space density increased by a factor of 29 or a factor of 70 discounting trap losses. In contrast to other cooling mechanisms, our scheme proceeds in a trap, cools in all three dimensions, and works for a large variety of polar molecules. With no fundamental temperature limit anticipated down to the photon-recoil temperature in the nanokelvin range, our method eliminates the primary hurdle in producing ultracold polyatomic molecules. The low temperatures, large molecule numbers and long trapping times up to 27 s will allow an interaction-dominated regime to be attained, enabling collision studies and investigation of evaporative cooling toward a BEC of polyatomic molecules.The ability to prepare ultracold molecular ensembles has an application potential akin to that of ultracold atoms some decades ago. In fact, the association of KRb dimers [16] as well as the laser cooling of SrF [17] has brought fascinating physics within reach. However, both approaches are restricted to a highly specialized set of purely diatomic molecule species. In order to investigate fundamental physics based on relativistic effects near heavy nuclei or parity violation effects in chiral molecules, or to study molecules of astrophysical, biological, or chemical interest, a more general approach to preparing ultracold molecular ensemble is imperative. This holds in particular for the rich chemical variety of carbon-, nitrogen-, or oxygen-based molecules for which the constituent atoms have not even been laser cooled. Devising a dissipative process to cool such molecules into the ultracold regime has been an exceedingly challenging problem. The standard approach for atoms, laser cooling, is in general impossible for molecules due to the lack of suitable cycling transitions. Creating an artificial cycling transition via cavity cooling [18] has not been demonstrated despite substantial experimental [19] and theoretical [20][21][...

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Section: Methodsmentioning

confidence: 99%

Sisyphus cooling of electrically trapped polyatomic molecules

Zeppenfeld

Englert

Glöckner

et al. 2012

Nature

192

188

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“…We follow the usual derivation of the semiclassical impact-parameter sudden approximation for collisions between two polar molecules.32,33 In a space-fixed axis . H. Alexander and A. E. DePristo system, where the z axis refers to the initial relative velocity vector, the dipole-dipole intermolecular potential is6,14 V(rltr2,R) = -(64 3/45)1/2µ1µ2 -3 X (lm1lm2\ll2m)Ylmi(rl)Ylm2(r2)Y2m*(R) (1) m^rri2 where the subscripts 1 and 2 refer to the two interacting molecules of dipole moments µ and µ2, (/i/n1i2m2|/1(2to) is a Clebsch-Gordan coefficient,36 and rb r2, and R describe, in a space-fixed system, the two diatomic molecular axes and the vector joining the centers of mass of the two molecules. Within the approximation of a constant-velocity straight-line trajectory, the explicity time dependence of the vector R can be expressed by…”

Section: Sudden Approximationmentioning

confidence: 99%

“…Rotationally inelastic collisions between polar molecules, where the long-range dipolar interaction provides the necessary torque, have long provided the paradigm for rotational energy transfer in molecular collisions.1 *Spectral line broadening, which gave early indirect evidence for these processes, was interpreted within first-order perturbation theory.2, 3 The first direct probe of the kinetics of rotational energy transfer was provided by microwave 1 Research supported by the National Science Foundation, Grant double resonance experiments, a technique pioneered at Ottawa4 and at Harvard in the research group of E. B. Wilson, Jr. 5 In a landmark calculation Rabitz and Gordon6 used the firstand second-order Born approximations to determine rotationally inelastic cross sections and energy transfer rates for the HCN-HCN and ICN-ICN systems. Good agreement with the experimental double-resonance results was obtained.…”

Section: Introductionmentioning

confidence: 99%

An adiabatically corrected sudden approximation for rotationally inelastic collisions between polar molecules

Alexander¹,

DePristo²

1979

J. Phys. Chem.

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Adiabatically Corrected Sudden Approximation 2v5°, v2 + j»5, 2v2, and zq by numerous long-range and local resonances that we have positively identified, it is no wonder that all these states will be populated shortly after i>3 = 3 itself. This should explain why the risetime of the fluorescence at 3000 cm"1 is so short.These phenomena should of course also be introduced to explain all the processes where methyl fluoride absorbs energy from a C02 laser such as Q switching, far-infrared lasers, and two-photon absorptions.Acknowledgment. The author was a research fellow in Bright Wilson's group during the academic year 1965-1966. He is pleased to be able to contribute to this Festchrift to testify how fruitful was his association with Bright Wilson.The author is indebted to Dr. G. Guelachvili who provided the spectrum of CH3F.for an integer value of J'.. If this were the case, one would have exactly = 2We" and Wc = M(2[J\J'+ 1) -K(K + 1)]",/2).

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“…the present molecules seemed particularly relevant; (cf. the extensive infrared data on this molecule [7][8][9][10][11][12]). Such a study should make clear which polarizability component dominates the scattering for any fundamental.…”

Section: Introductionmentioning

confidence: 99%

The vapour phase Raman spectra, Raman band contour analyses, Coriolis coupling constants, and force constants for the molecules F¹²CH₃, F¹³CH₃, H¹²CCl₃and H¹³CCl₃

Clark¹,

Ellestad²,

Escribano

1976

Molecular Physics

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The vapour phase Raman spectra of the molecules F12CHa, FlaCHa, H12CC13, and HlzCCla have been recorded at pressures of ca. 1 atmosphere over the fundamental frequency regions. Partly resolved rotational structure is reported for some fundamentals of methyl fluoride. The Raman band contours of the e-species fundamentals have been analysed to yield Coriolis constants from which e-species force constants have been calculated. The Coriolis and force constants so determined are compared with those based on analyses of appropriate vapour phase infra-red spectra.

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The Infra-Red Spectrum of Methyl Fluoride

Cited by 19 publications

References 9 publications

Sisyphus cooling of electrically trapped polyatomic molecules

Sisyphus cooling of electrically trapped polyatomic molecules

An adiabatically corrected sudden approximation for rotationally inelastic collisions between polar molecules

The vapour phase Raman spectra, Raman band contour analyses, Coriolis coupling constants, and force constants for the molecules F¹²CH₃, F¹³CH₃, H¹²CCl₃and H¹³CCl₃

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The Infra-Red Spectrum of Methyl Fluoride

Cited by 19 publications

References 9 publications

Sisyphus cooling of electrically trapped polyatomic molecules

Sisyphus cooling of electrically trapped polyatomic molecules

An adiabatically corrected sudden approximation for rotationally inelastic collisions between polar molecules

The vapour phase Raman spectra, Raman band contour analyses, Coriolis coupling constants, and force constants for the molecules F12CH3, F13CH3, H12CCl3and H13CCl3

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The vapour phase Raman spectra, Raman band contour analyses, Coriolis coupling constants, and force constants for the molecules F¹²CH₃, F¹³CH₃, H¹²CCl₃and H¹³CCl₃